svcs.ebay.com refused to connect

[densini50]

My https call is not answered by svcs.ebay.com:

http://svcs.ebay.com/services/search/FindingService/v1?OPERATION-NAME=findItemsByKeywords&sortOrder=...

where I scrambled y APP key any letter or digit replaced by #. Note that my APP key is for sandbox, not production, but as I understand it should still work.
I think there is no problem with this request but apparently there is an issue. Can anyone suggest where to look? This is my first experience with eBay.

Thank you!

[shipscript]

Please ensure that the endpoint uses the https protocol. eBay recently dropped access to the non-secure http endpoint.